This invention relates to a vessel speed detecting device and more particularly to an improved, simplified arrangement for providing an accurate indication of the speed of travel of a watercraft.
A wide variety of devices have been proposed for giving an indication of watercraft speed. Many of these devices are quite complicated and require complex transmission systems for transmitting a speed signal from the speed indicating device to the indicator in the operator's compartment of the watercraft. Recently, it has been proposed to provide a device that senses dynamic water pressure and utilizes a semiconductor pressure sensor for providing the speed signal. Such an arrangement is shown in copending application Ser. No. 160,124, filed Feb. 25, 1988, in the name of Kazuhiro Nakahama et al, entitled "Speedometer For Marine Vessels", and assigned to the assignee of this application. Although that type of device provides a very simple and yet highly effective arrangexent for indicating watercraft speed, there are some conditions in which the actual speed of the watercraft may deviate from the indicated speed generated by the pressure signal. For example, when there is an abrupt change in watercraft speed, particularly a sudden deceleration, the pressure signal may not be accurately indicative of actual watercraft speed.
It is, therefore, a principal object of this invention to provide an improved speed sensor for a watercraft that will give good and accurate readings even under extreme transient conditions.
It is a further object of this invention to provide a vessel speed detecting device that will give an accurate vessel speed even under abrupt transient conditions.